Sketch.js is a jQuery plugin that makes it simple to create a canvas for drawing.

Buttons can be used to change the size & colour of the marker, select an eraser or download the drawing. The buttons use the HTML5 data attribute to update the canvas and can all be be styled with CSS.

Power Tip is a lightweight (6kb minified) jQuery tooltip plugin with a powerful set of features including:

Hover intent – Prevents the tooltip from opening on accidentally hovering over the element.

Queuing – The previous tooltip can be gracefully closed before a new one is opened.

Multiple instances.

Smart placement – Keeps tips inside the viewport.

Fade In/Out.

Keyboard navigation compatible.

The plugin supports eight different placements as well as a mode to follow the mouse inside a larger container element. It is also possible to add interactive content inside the tooltips such as links.

There is an API that will allow you progmatically show and hide tips. There are a number of options and events for customisation and everything is extremely well documented.